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Nov. 13, 1928.

T. B. HARPER DEVICE FOR COMPUTING INTERESTk Filed April 24, 1926 2Sheets-Sheet l f s M f a V d 7, 6 0 J j a.

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T. B. HARPER DEVICE FOR COMPUTING INTEREST Nov. 13, 1928.

Filed April 24. 1926 2 Sheets-55,981,

Patented Nov. 13, 1928.

UNITED STATE-s PATENT OFFICE.

`l'.HEODORE B. HARPER, OF HARTFORD, CONNECTICUT, ASSIGNOR TO THE HARPERMANUFACTURING CO., INC., OF HARTFORD, CONNECTICUT, A CORPORATION OF CON-N ECTICUT.

DEVICE FOR COMPUTING vINTIEIRIIS'L.

Application led April 24, 1926. Serial No. 104,465.

The invention relates to new and useful improvements in a device forcomputing interest on bonds, notes and the like.

An object of the invention is to provide a device of the above characterwhich is very simple in construction and which requires only one settingfor a given day in the ear whereby the accrued interest on bonds rom thedate of maturity to the date of computing interest may be quicklydetermined.

A further object of the invention is to provide a computing deviceof theabove char`r acter which may be used over and over again.

These and other objects will in part be obvious and Will in partbehereinafter more ff fully disclosed.

In the drawings which show by way of illustration one embodiment of theinvention- Figure l is a frontview of a portion of a device embodyingthe improvements;

Fig. 2 is a longitudinal sectional view through the shiftable lineindicating device associated with the cards containing the coma@ putedinterest;

Fig. 3 is a, sectional view on the line 3 3 of Fig. l, and y l Fig. 4 isan enlarged face view of one'of the cards having the computed interestwhich is used in connection with my device.

- The invention is directedy broadly to a device for computing interestwhich is accomplished by the use of a series of cards termed daycardswand a shiftable line indicating device whereby the line containingthe computed accrued interest on the card is found ena note or bond dueat a predetermined time in a given month of the year. Each day card hasa certain grouping of figures. The 40 figures are grouped verticallyunder the value to be computed, as for example, one thousand andmultiples thereof. These figures y are computed interest based oncertain factors, and they are arranged in groups horizontallycorresponding to the rate of interest paid. The cards in the day seriesare numbered from one to thirty. The interests indicated on these cardsare preferably accrued interests, and each line contains the computedinterest for different periods of time. One line will give the computedinterest on a value in the groupy in which it is arranged at the rate inthe group in which it is arranged for the number of days in the thirtypreceding the date of the day card. The next line will contain thecomputed interest on this fractional portion of the thirty days, plusone month, or an additional thirty days, while the next line includesthe computed interest for this fractional portion of a month, plus twoperiods of thirty days, and so on, until siX lines are provided whichrepresent/the computed interest for. five months, the fractional portionof the month in which the interest is computed. A card so constructed isparticularly designed to be used in the computing of interest which ispayable semi-annually. If it is desired to compute interest payableannually, then twelve lines would be provided on the day card.Associated'with this series i of thirty day cards, is a line indicatingdevice which is set only once. for each month in which the interest iscomputed. This line indicating device contains characters which selectthe .line where the accrued interest will be found on bonds for anymonth in the year. By one setting of this indicating device, and theselecting of the card for the day in the month on which the accruedinterest is to be determined, one can quickly determine the line on thecard where the accrued interest is found, for a given rate and for agiven value or multiple thereof, which bond is due any month in theyear.

Referring more in detail to the drawings, my device includes asupporting bracket 1 which may be inclined for convenience in the usingof my device. This bracket is supported in any desired way. Attached tothis bracket are the day cards, two of which are indicated in part inFig. l. The cards are indicated at 2 and 3. The bracket is provided withcurved wires 4, 4 of the character commonly used in connection withcalendars or the like. The cards are provided with perforations asindicated at 5, 5, and the wires 4 are inserted through theperforations. As shown in Fig. l, there are two groups or stacks ofcards 2 and 3, and of course, there are two pairs of wires 4. Beforeproceeding further with the description of the device 'shown in Figures1 to 3, I will describe more in detail the day cards, one of which isindi-y cated at 2 in Fig. 4. This day card selected for illustration isthe tenth card in the group of thirty, and it is numbered 10. It 1sunderstood that the cards will be numbered consecutively from 1 to 30,and will be preferably stacked on the bracket one above another. Thecard may be readily turned over back of the bracket so as to expose thedesired day card. 0n the tenth of the month, the tenth day card isselected for computing in terest. The figures 1 to 9 included in thehorizontal lines at the top of the card and parallel therewith,represent amounts of one thousand, two thousand, three thousand, etc.,that is, multiples of one thousand. These, of course, represent so manydollars. The figures in the vertical groups at the sides of the card arethe rates per year, being eight per cent, seven percent, six percent,etc., on the particular card illustrated. The figures in the lines undereach rate group indicate the computed interest on the amount at the headof the column of figures, and at the rate at the side of the group forperiods of time covering nine days, that is, the days preceding thetenth of the thirty day period. This interest is expressed in line 1 ofeach group. In line 2 of each group is the interest for this fractionalportion of the thirty days, that is, nine days, plus the additionalinterest of thirty days. In the next line, is the computed interest on afurther additional thirty days, and so on, down to the sixth line.

In Fig. 1 of the drawings, there are shown two day cards numbered 10.The reason for this is that the card at the right bears the accruedinterest at eight percent, seven percent, etc., While the card at theleft bears the accured interest at the rates of seven and onhehalfpercent, six and one-half percent, etc. It will be understood, ofcourse, that these cards maybe made in different sizes, and that groupsfor stated values may be added, and that different rates of interest maybe added, if desired. The device which I have shown in the drawings isparticularly useful in determining the accrued interest on bonds whichmature on the first day of the thirty day periods of the year, and atYrates of interest from three and one-half to eight percent, although Ihave only shown the figures for the rates of interest from six andone-half to eight percent. The values computed run from one thousand tonine thousand dollars.

Associated with these day cards is a character bearing device whichindicates the particular line in which the computed interest will befound on a bond maturing on the first of any month in the six monthperiod in which the bond runs. This device consists of a support 6 whichis rigidly attached to the bracket 1 by screws 7. There are spacing lugsprovided so that the support G is slightly offset from the bracket 1(see Fig. 3). The Wires 4 are secured t0 the bracket 1 by suitable`clamping nuts 9 and 10. Both ends of the wire are clamped to the bracket1 by these nuts, and the wires encircle the support 6 so that the cardsmay be turned from the front side of the bracket to the rear sidethereof. Mounted in this support is a slide 11. The slide 11 is providedwith characters indicating the months in the year, and when figuringsemiannual interest, these months may be grouped as follows January andJuly; June and December; May and Nw vember; April and October, March andSeptember and February and August. These months are six months apart, orare semiannual periods for computingI interest.

'The front of the support is also provided with openings 14, 15, 16, 17,18 and 19. Gn the face of the support are printed charactersrepresenting the months grouped as above stated. The opening 14C isassociated with the months of January and July; while the opening 15 isassociated with the months of February and August, and so on asindicated in Fig. 1 of the drawings. The slide 11 is provided withcharacters. The characters I have selected are numbers from 1 to 6, andthese numbers are used for indicating the lines in whichthe computedinterest will be found. These numbers are so placed on the slide, thatupon a shifting of the slide so as to expose a certain grouping ofmonths at the opening 13. there will be a predetermined exposure offigures through the openings from 14 to 19, inclusive. As shown in Fig.1 of the drawings, for the month of May or for the month of November,the characters in the openings 14C to 19, are 5, 4, 3, 2, 1, (i,respectively.

Let us assume that the device is to be used for figuring accruedinterest on the tenth da y of May. Then the slide isset as indicated inFig. 1, so as to bring to View the character indicating the month of Mayin the opening 123. The card numbered 10 is exposed to view. All theaccrued interests on bonds payable semi-annually during May, and thefive months preceding May, will be found on this day card at the rategiven on the card and for the value indicated on the card. For example,let us suppose it is desired to determine the. accrued interest on abond payable on the first day of January for one thousand dollars. Theopening 14C is the opening associated with the month of January, andthrough this opening, the figure 5 is viewed. This means that thecomputed interest on the bond due on the first of January at eightpercent for the amount of one thousand dollars will be found in thefifth line, and this indicates that the accrued interest is 9,428.66. Ifthe bond is due in December, then the numeral G is the indicatingcharacter which determines the line on the day card where thecomputedinterest will be found, and this shows that the computedinterest on this bond due December 1st. ou thc tenth day of May, at therate of eight percent per year, and for an amount of one thousanddollars, is $35.33. It is thought that no further concrete examples arenecessary, but it will be obvious that the accrued interest on a bonddue at any month in a six month period and for amounts of one thousandand multiples thereof, can be readily determined from this day card.Each morning the day card for the day is selected; each month the slideis moved so as to position the slide for a particular month in which theinterest is to be computed. No further settings of the slide arenecessary for the period of thirty days, and no further shifting of thecards is necessary, except turning the cards so as to select theparticular day on which the interest is computed. Therefore, after theproper card has been selected and the month set in which the interest isto be computed, all the computings for a single day can be read from asingle card, or from the two cards, when two cards are used withdifferent rates thereon.

It will be understood, of course, that if the bonds which are to befigured, mature on the fifteenth day of the month instead of the firstday of the month, then a different card is selected, as the interestswill be slightly different. The same principle of operation, however, isused. i

While I have shown a slide with characters thereon which may bepositioned for determining the particular lines in a given monthindicating the accrued interest on bonds maturing in certain statedmonths, it will be understood that other devices may be used forselecting the line in which to find the accrued interest.

In a companion case, Serial Number 104,464 filed by me of even dateherewith, I have shown and described in detail a series of month cardsfor accomplishing the same result. Other ways may be devised foraccomplishing the same result without de arting from the spirit of theinvention as set orth in the appended claims.

Having thus described the invention, what I claim as new and desire tosecure by Letters- Patent, is-

l. A device for computing interest comprising a series of day cards,each card representing a stated day in the month and having indicatedthereon the interest on a unit amount and multiples thereof, at variousgiven rates, for the period of days in the month preceding the stateddate, and also for each added month from maturity, and means associatedwith any selected card for indicatl inga` line on the day card oppositea given rate containing the calculated interest on a unit amount ormultiples thereof from the date of maturity.

2. A device for computing interest comprising a series of day cards eachcard representing a stated day in the month and having indicated thereonthe interest on a unit amount and multiples thereof at various givenrates for the period of da s in the month preceding the stated date analso for each added month from the date of maturity, and meansassociated with the day cards for computing on a given day of a givenmonth the period of days preceding the given day of the given month fromgiven dates of maturity and indicating on the day card opposite a givenrate the calculated interest on a unit amount or multiples thereof forsuch period of time.

In testimony whereof, I aliix my signature.

THEODGRE B. HARPER.

